Claim differentiation used to defeat independent claim?

[dbmax]

Here's an extreme hypothetical.

1) An aparatus comprising a light source configured to emit light at a wavelength of 475nm....
...
20) An apparatus according to claim 1 wherein said light source is configured to emit blue light.   

Under the Doctrine of Claim Differentiation, can Claim 20 in this example (or any better example you might have) lead to a finding that Claim 1 is indefinite?

More generally, is there a danger in adding a dependent claim which contains a limitation which might be either inherent to or broader than the independent claim?

[bluerogue]

I don't think it'd lead to a finding that claim 1 is indefinite, but you'd probably run into the rarely used 112d for claim 20.

A dependent claim needs to further limit the independent claim.  A claim that is broader would not further limit. 
A claim that is inherent would also not further limit and you'd probably run into a duplicate claim objection as well.

[still_learnin]

1) An aparatus comprising a light source configured to emit light at a wavelength of 475nm....
20) An apparatus according to claim 1 wherein said light source is configured to emit blue light.   

I don't think it'd lead to a finding that claim 1 is indefinite, but you'd probably run into the rarely used 112d for claim 20.
A dependent claim needs to further limit the independent claim.  A claim that is broader would not further limit. 

Interesting issue. I'm not positive that the dependent is broader. I'll assume that "blue light" means "wavelength of 450-495 nm."

How do we interpret the combination of limitations in the dependent? How about this:

An apparatus configured to emit light at a wavelength of 475nm AND configured to emit light at 450-495 nm.   

Wouldn't that mean the apparatus must be able to emit the specific wavelength and the wider band? And if we interpret that way, the dependent is narrower, right?

I said "be able to" because of "configured to." Which made me wonder if the narrowing -- which results from adding further capability -- is an artifact of this way of claiming.

So, thinking further, what happens in a method claim? For a method, I think it depends on precisely how you choose to narrow.

1) An method of curing rubber comprising
emitting light at a wavelength of 475nm....
20) The method of claim 1 wherein the emitted light has a wavelength between 450 nm and 495 nm.
21) An apparatus according to claim 1 further comprising emitting blue light.   
22) An apparatus according to claim 1 where the emitting further comprises emitting blue light.   

I think method claim 20 is in fact broader than its independent. Claim 21 clearly requires two emissions, one at a specific wavelength and one at a range, which makes it narrower. I can't decide whether claim 22 requires two emissions or not.

[bluerogue]

Wouldn't that mean the apparatus must be able to emit the specific wavelength and the wider band? And if we interpret that way, the dependent is narrower, right?
An apparatus configured to emit light at a wavelength of 475nm AND configured to emit light at 450-495 nm. 

I said "be able to" because of "configured to." Which made me wonder if the narrowing -- which results from adding further capability -- is an artifact of this way of claiming.
So, thinking further, what happens in a method claim? For a method, I think it depends on precisely how you choose to narrow.

22) An apparatus according to claim 1 where the emitting further comprises emitting blue light.   
I can't decide whether claim 22 requires two emissions or not.

Interesting question indeed.  Easy answer is that you should probably avoid such claiming lest you end up rolling the dice at the PTO and Fed. Cir.

In the apparatus case, it probably depends on how "configured to emit light at 450-495 nm" is interpreted.  One interp would be that the device emits light at 475 and also throughout the entire range of 450-495.  That's arguably narrowing since the device now has to emit more than just 475.  In a different interpretation where the device is capable of emitting any wavelength from 450-495, and it already emits 475, then it's probably not limiting because if it's capable of emitting light at 475, then it meets the range limitation inherently as the device in claim 1 emits light in that range already.

As to the hypothetical claim 22, I'm not sure either.  I'd probably subject it to a 112b to have you clarify what you mean by "emitting blue light." Does it emitting only 475 light meet the limitation or does it emit the entire range of 450-495?  Both would be valid interpretations and absent any further definition would not appraise the public of the metes and bounds of the application and all that.

[dbmax]

Wouldn't that mean the apparatus must be able to emit the specific wavelength and the wider band? And if we interpret that way, the dependent is narrower, right?

Interesting question indeed.  Easy answer is that you should probably avoid such claiming lest you end up rolling the dice at the .... Fed. Cir.

still_learnin,

Right. Clearly, a case of my typing faster than I could think, which adds even more weight to my concern.

Presuming that a more subtle (and true) redundancy than the one I attempted to illustrate survived to issue, is there any case where an independent claim has been so constructed during litigation as to be found indefinite by differentiation with a dependent claim?

I'm guessing that a such a result would be found to violate one of the "canons" of claim construction, but as bluerogue suggests, who wants to go to CAFC to find out?

[NJ Patent1]

"Under the Doctrine of Claim Differentiation, can Claim 20 in this example (or any better example you might have) lead to a finding that Claim 1 is indefinite?".  My best answer is maybe, but don't count on it.  It is my understanding that the "doctrine" is more of a "presumption".  In your hypo, claim 20 limits "blue" (= 450 to 950 nm) to one specific wavelength (475 nm) that is "inherent" in the limitation "blue".  Looks like a proper dependent claim to me.  As has been noted, a dependent claim that attempts to broaden the scope of the claim from which it depends is of improper and should have been objected to by the Examiner. 

[dbmax]

It is my understanding that the "doctrine" is more of a "presumption". 

Thanks NJ Patent1.

Found this in support.

Zircon v Stanley Black & Decker, Zircon Corp. v. Stanley Works, 713 F. Supp. 2d 881. 
citing Laitram Corp. v. Rexnord, Inc., 939 F.2d 1533, 1538 (Fed. Cir.  1991)  (quoting Autogiro  Co.  of  Am.  v.  United  States, 384 F.2d 391, 404 (Ct. Cl. 1967) ("Claim differentiation is a  guide,  not  a  rigid  rule.  If  a  claim  will  bear  only  one  interpretation, similarity will have to be tolerated.")).